He will be with you . . . . . . . . a moment. A. of B. in C. about D. on

The correct answer is: in.

The word “in” is used to indicate a period of time. In this case, it is used to indicate that the person will be with you in a short period

The other options are not as appropriate in this context. The word “of” is used to indicate possession or association. The word “about” is used to indicate a topic or subject. The word “on” is used to indicate a location or position.

Here are some examples of how the word “in” can be used to indicate a period of time:

• I will be back in a moment.
• The meeting will start in an hour.
• The test will be over in 30 minutes.

I hope this helps!